Publication Date

2003

Document Type

Dissertation/Thesis

First Advisor

Corwin, James V.

Degree Name

Ph.D. (Doctor of Philosophy)

Department

Department of Psychology

LCSH

Cerebrovascular disease--Treatment||Neglect (Neurology)--Treatment

Abstract

In approximately 40% of all cases of right hemisphere stroke, patients experience a complex array of debilitating neurological deficits known as the neglect syndrome. This devastating and crippling condition is characterized by impairments in spatial and attentional processing, lack of affect, and unresponsiveness to the side of space opposite the brain lesion. Even following significant recovery, one of the major symptoms of neglect, extinction to bilateral simultaneous stimulation (extinction), often remains. Currently, there are no effective generalizable treatments of any kind for patients with neglect. A rat model of the neglect syndrome that demonstrates dramatic behavioral, anatomical, and pharmacological similarities to the human has been developed to investigate behavioral recovery of function from neglect. Studies utilizing the rodent model suggest that recovery from neglect may be due to plastic changes occurring in one area of the brain, the dorsal central striatum (DCS). Given the apparent role of the DCS in neglect and recovery from neglect, two important issues arise: is the DCS the site of drug action in studies that demonstrate acute behavioral recovery following systemic injection of the dopamine agonist apomorphine, and is the DCS involved in extinction, the most persistent symptom of neglect? Results from the current study demonstrate that direct infusion of apomorphine into the DCS, but not a more lateral striatal control area, was effective in producing acute behavioral recovery from neglect. This finding represents an important step in the development of dopamine agonist therapy in the treatment of humans with neglect. With regard to the second issue, prior to the current study, the importance of the DCS in extinction had not been investigated. Further, it was also unknown whether extinction was simply a less severe form of neglect or a unique behavioral phenomenon separate unto itself. Results from the current study demonstrate that DCS-lesioned animals, despite exhibiting neglect, do not exhibit extinction. This finding suggests that neglect and extinction are dissociable and do not share the same neural substrates. These findings are particularly important for the development of therapeutic interventions, suggesting that neural substrates other than those involved in neglect should be investigated.

Comments

Includes bibliographical references (pages [110]-118)

Extent

vi, 124 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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